The aim of the experiments performed in this work was to develop a biofilm airlift suspension (BAS) process for the degradation of a mixture of organic sulfonates contained in the infiltration water from a contaminated site. To achieve this goal, active biomass growing on the contaminating xenobiotic organics as the sole source of carbon was obtained by enriching a mixed microbial culture sampled from an activated sludge treatment plant. After kinetic characterisation, the enriched culture was inoculated in the BAS reactor, where it colonised carrier particles and formed stable and uniform biofilms. In spite of the slow growth and degradation kinetics (mu(max)=0.014 h(-1)), due to high biomass concentration (up to 12 g(VS)L(-1)) a high rate process was performed in the BAS reactor, achieving a degradation capacity of 8.7 kg(COD)m(-3)d(-1), with an overall degradation efficiency of 70% based on COD measurements.